An allergy is the overreaction of the immune system to something that’s harmless. Allergic rhinitis is irritation and swelling in the nose. A chain of events starts when allergens are breathed in from the air. The most common are from grasses, trees, weeds, or animals.
Once in the nose, mast cells release histamine. This causes swelling in the blood vessels and mucous membranes in the lining of the nose. A reaction can happen quickly and involves:
- Runny or itchy nose
- Watery, itchy, or red eyes
- Sneezing
- Coughing
This is a very common problem for millions of people in the US. But, they don’t happen to all people.

There are 2 types:
- Seasonal—Happens mainly in the spring, summer, or early fall. Causes are from grasses, trees, weeds, or mold spores in the air.
- Perennial—Happens year-round. Causes are from dust mites, cockroaches, animal dander, or mold spores. For some, food allergies may cause this type.
In most cases, allergies are mild and only cause discomfort. But for many people, they can be tied to:
- Asthma
- Ear infections
- Sinus pain or infection
- Sore throats
- Irritability
- Feeling tired
- Dark circles under the eyes
- Headache
- Pink eye
Revision Information
- Reviewer: EBSCO Medical Review Board Marcin Chwistek, MD
- Review Date: 09/2018 -
- Update Date: 10/15/2018 -